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Definition of radiation

radiation

/ˌreɪ.diˈeɪ.ʃən/
ra · di · a · tion
Plural:radiations
•
Adjective:radiational
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radiation Lexical Profile

radiation Game Scores & Validity

• noun

1

The emission or transmission of energy in the form of electromagnetic waves or moving subatomic particles through space or a material medium.

Example

"Astronauts aboard the space station are shielded against harmful cosmic radiation."

2

The medical use of high-energy rays or particles, such as X-rays or gamma rays, to destroy cancer cells and shrink tumors; radiotherapy.

Example

"The oncologist recommended six weeks of radiation following the surgery."

3

Divergence out from a central point, in particular the evolutionary divergence of an ancestral group of organisms into multiple distinct forms adapted to different ecological niches.

Example

"The fossil record reveals a rapid evolutionary radiation of mammals after the extinction of the dinosaurs."

Synonyms
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Antonyms
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• Rhymes for radiation

• Nearby Words

radiantly
radiate
radiated tortoise
radiation
radiator
radical
radicalism

Word Origin & Etymology

Borrowed from Latin radiatio ('a shining or emitting of rays'), from the verb radiare ('to beam, shine'), which derives from radius ('spoke of a wheel, beam of light').

Cite this Entry

Wordmom. (2026). Definition of Radiation. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/radiation
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